1. Field of the Invention
The present invention relates to a benzimidazole compound or a salt thereof, or a solvate of these, useful as a gastric acid secretion inhibitor.
The present invention also relates to a benzimidazole compound or a salt thereof, or a solvate of these, useful as a therapeutic agent or prophylactic agent for acid-related diseases or symptoms (especially gastroesophageal reflux diseases, symptomatic gastroesophageal reflux diseases, gastric ulcers and duodenal ulcers).
2. Description of Related Art
Peptic ulcers such as gastric ulcer and duodenal ulcer are conceivably caused by the disruption of the balance between aggressive factors, such as acid and pepsin, and defensive factors, such as the mucus and blood flow, leading to autodigestion.
The peptic ulcer is principally treated by medical care, so that various drug therapies have been tried as the medical care. Particularly, in recent years, a medicament capable of specifically inhibiting H+/K+-ATPase, which is an enzyme present in the parietal cells and responsible for the final stage of gastric acid secretion, thereby suppressing gastric acid secretion and inhibiting autodigestion, has been developed and put to clinical use. Examples of such a medicament include omeprazole, esomeprazole, pantoprazole, lansoprazole, and rabeprazole.
These medicaments have excellent therapeutic effects; however, a medicament that more persistently inhibits gastric acid secretion, is safer, and is appropriately physicochemically stable has been still desired to be developed. In particular, it is also suggested that the cure rate of gastroesophageal reflux disease may be improved by maintaining the intragastric pH at a high value for a long time (Non-Patent Document 1).
Compounds particularly relevant to the present invention are described in Patent Documents 1 and 2. However, the compounds disclosed in these patent documents differ in chemical structure from the compounds specifically described in the present invention.    Patent Document 1: WO 91/19712    Patent Document 2: JP-A-59-181277    Non-Patent Document 1: Digestion 1992; 51 (suppl 1): 59-67